what i did was i belive hey are #16 o-rings i use those as detents, they work amazing
try it

If you're lazy like me, you can get one of those rectangular pencil erasers, then cut a thin, even slice with an exact knife or a really sharp kitchen knife. Get a hole puncher and voila! You've not got spacers that fit in your ram. It might work for the o-ring detents depending on the size of your hole puncher. Honestly, i think that's easier than cutting the eraser off of a number 2 pencil for some reason. Other things that work is sheets of neopreme (which is probably more durable) but a pain in the butt to get down to the right width.